I think it might help to take a step back and understand the workflow for our asynchronous analytics endpoints. There are several steps that need to be taken. This post explains each of them. After you create the job, which you’ve already done*, you must actually download the gzipped file (once it’s ready), unzip it, and check the contents.

* You’ve only created the job, but I don’t see subsequent steps where you’re actually retrieving the data.